I. Field of the Invention
A stop valve for controlling the flow of fluid through fluid lines and, in particular, to a stop valve manufactured through a multi-stage molding process to include a sealingly resilient fluid control sleeve and a more rigid valve stem for rotation of the sleeve.
II. Description of the Prior Art
A stop valve is a shut-off valve to permit the replacement of washers or other repairs to be accomplished on a plumbing fixture without shutting down an entire plumbing system. The stop valve is commonly located in the fixture supply line between a wall and the fixture. Stop valves are generally available in two basic styles. One style is known as an angle stop valve that has the inlet and outlet of the valve at right angles to each other. The other standard configuration is a straight-through arrangement wherein the inlet and outlet are coaxially aligned with each other.
One type of effective and efficient angle stop valve is disclosed in U.S. Pat. Nos. 4,562,994 and 4,609,177 to Turner et al and incorporated herein by reference. Another example of an angle stop valve is disclosed in U.S. Pat. No. 5,076,540 to Murphy and U.S. Pat. No. 5,695,169 to Higgins.
In all of these previous disclosures, the stop valve has a control sleeve made from low friction resilient thermoplastic material such as a Santoprene™ material. The handle is formed from a durable plastic material such as ABS. The operation of the valve from the open to the closed position is a simple quarter turn of the handle. The resilient plastic material of the valve control sleeve provides for a complete shut off of the water supply. As with all stop valves, these plastic stop valves may be left in the open position for many months and even years without being touched. The long period of time between use of the shut off valve allows for significant mineral deposit on the valve which may bind the valve within the valve body. The resulting binding necessitates the use of increased torque to be applied onto the valve to break the binding layer of mineral deposits in order to move the valve to the closed or shut off position. Additionally, stops need to be resistant to oxidative agents, freezing conditions and aggressive water conditions. Prior inventions containing a single plastic control sleeve could not provide sufficient performance under all water conditions. The torque required to break these binding barriers sometimes caused the valve stem to break, twist like a screw, or disconnect from the control sleeve leaving no means for closing the stop valve. The present invention overcomes the disadvantages of the prior known stop valves by using a multishot molding process to provide a control sleeve that has a flexible wall in the sealing area and a hard plastic stem for mechanical control.